dunnhumby Data Scientist Interview Questions
& Process

The interview process was terrible, disrespectful, and unprofessional. I was contacted for a Research Data Scientist role. Communication was minimal from the start; no intro call or role explanation, just an interview invite. The first interview, scheduled for an hour, was only 30 minutes. The hiring manager admitted he was new and the role was still being defined. After waiting three weeks with no update, I followed up with HR and was told I progressed. I chose a time for the next interview, but heard nothing. As the date neared, I had to find the hiring manager's contact myself to confirm the interview, which is unacceptable. The in-person interview was professional. I sent a thank-you email and got a timeline for an update, but the deadline passed without news. I followed up again and got a new timeline. When that deadline arrived, I asked for an update, but received no communication, and the deadline passed again. After chasing for a week (the third time), I finally got a brief rejection email from HR the next day. This email lacked any explanation, feedback, or apology, and was sent from a mobile with poor formatting and grammar. I even politely asked for feedback, but got no response. HR also falsely claimed they called me, which didn't happen; my phone was on, with no missed calls or voicemails, and no attempt was made to email. The whole process felt transactional, unprofessional, and disrespectful of my time. I have a very negative impression of the company's hiring approach and would strongly advise against applying unless you want to be treated this way.

The interview process involves three rounds. First, there's an HR Round for basic screening. If your resume is shortlisted, you'll proceed to an Aptitude test, which helps filter candidates. After that, there's a Group Discussion (GD) based on a case study, lasting about 2 hours, followed by a Personal Interview (PI). The PI includes an in-depth review of your resume and projects, a coding challenge (Python, SQL, or your comfortable language), and solving a case study live during the interview.

The interview process was conducted online and moved along pretty quickly. It consisted of 4 rounds. First, a HR rep called to chat about my background, pay expectations, and reasons for seeking a new job. Then, there was an online test with 30 multiple-choice questions and 2 coding problems focusing on Python and SQL; how tough it is really depends on your familiarity with the programming language, so brushing up is a good idea. The third round was a technical interview with a Lead Data Scientist, lasting about 60-75 minutes, covering SQL, Python pandas, k-means clustering, the elbow method, and previous projects. Finally, I met with the Hiring Manager for a 60-minute session where we discussed how I'd approach and solve a few open-ended business problems, similar to those in retail or grocery, and went deep into one of my past projects. They also asked why I was interested in dunnhumby.